Multilayered package with barrier properties

ABSTRACT

The present invention provides compositions useful as a barrier layer in, for example, packaging products. The compositions generally comprise a blend of (i) a polyester resin, preferably an aromatic polyester resin such as polyethylene terephthalate (PET) and (ii) a polyamide material (e.g., MXD6). The blend optionally may further comprise (iii) an oxygen scavenging material. The present invention also provides containers (e.g., containers formed by expansion of preforms) having a multilayered body-forming portion including: a layer comprising the aforementioned blend; and one or more layers of a formable polymer composition. The present invention also provides methods of making such containers.

RELATED APPLICATIONS

This application is a Continuation-In-Part of PCT/US01/145254 Oct. 31,2001 which claims benefit of 60/246,834 Nov. 8, 2000 and claims benefitof 60/273,610 Mar. 6, 2001 and PCT/US01/46050, filed on Oct. 31, 2001.

TECHNICAL FIELD

Within the packaging industry, there is a progressive change towards theuse of containers of plastic material. This relates to both containersfor beverages, including carbonated beverages, and containers for foods.As far as foods are concerned, there is an express desire in the artalso to be able to employ containers of plastic material for the storageof preserved foods. In all of these fields of application, theinsufficient barrier properties of the plastic material—and inparticular its insufficient capacity to prevent the passage of gases,for example oxygen and CO₂, vaporized liquids such as water vapor etc.entail that the shelf-life and durability of the products stored in thecontainers will be far too short.

A number of proposals have been put forward in the art to solve theabove problem, but the proposed techniques have failed to meetestablished demands of cost in combination with barrier properties inorder that containers of plastic material may successfully be employedwithin the above-outlined sectors. Examples of solutions proposed in theart include:

-   -   laminates in which two or more layers of plastic material are        combined with one another and in which the material in each        layer possesses properties which entail that, for instance, gas        penetration, light penetration or moisture penetration are        reduced;    -   constructions in which, for example, a metal such as aluminum is        encapsulated between the plastic materials or, for instance,        forms the inner surface of the container; and    -   constructions in which a barrier material other than metal is        applied interiorly or in layers between the plastic material.

Solutions are also known in the art in which plastic materials ofdifferent types are mixed and thereafter molded to form containers.Thus, for example, it is previously known to produce containers ofplastic material in which the plastic material consists of a mixture ofPET and polyamide. See, e.g., U.S. Pat. Nos. 5,034,252; 5,281,360;5,641,825; and 5,759,653. Unfortunately, these attempts have yieldedcommercially unsatisfactory results, for example, poor layer-to-layerlamination strength.

From the foregoing, it will be appreciated that what is needed in theart is improved plastic containers having even greater barrierproperties for gases such as oxygen and CO₂. Such containers andmaterials and methods for preparing the same are disclosed and claimedherein.

SUMMARY

The present invention relates to compositions useful as a barrier layerin, for example, packaging products. The compositions generally comprisea blend of (i) a polyester resin, preferably an aromatic polyester resinsuch as polyethylene terephthalate (PET) and (ii) a polyamide material(e.g., MXD6). The blend optionally may further comprise (iii) an oxygenscavenging material.

The present invention also relates to containers (e.g, containers formedby expansion of preforms) having a multilayered body-forming portionincluding: a core layer comprising the aforementioned blend; and innerand outer layers of a formable polymer composition. The presentinvention also relates to methods of making such containers.

DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a three-layer preform according tothis invention;

FIG. 2 is a cross-sectional view of a five-layer preform according tothis invention;

FIG. 3 is an elevational view of a three-layer hot-fill containeraccording to this invention;

FIG. 4 is an enlarged fragmentary sectional view taken through thesidewall of the container of FIG. 3, showing the three-layers;

FIG. 5 is an elevational view of a five-layer ketchup containeraccording to this invention; and

FIG. 6 is an enlarged fragmentary sectional view taken through thesidewall of the container of FIG. 5, showing the five layers.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

In one embodiment, the present invention relates to compositions usefulas a barrier layer in, for example, packaging products. The compositionsof this embodiment generally comprise a blend of (i) a polyester resin,preferably an aromatic polyester resin such as polyethyleneterephthalate (PET) and (ii) a polyamide material. The blend optionallymay further comprise (iii) an oxygen scavenging material.

The blend suitably comprises a formable polyester. Suitable formablepolyesters for use in the present invention include PET (e.g., virginbottle grade PET, post-consumer PET (PC-PET), etc.), cyclohexanedimethanol/PET copolymer (PETG), polyethylene naphthalate (PEN),polybutylene terephthalate (PBT), etc.

Phthalic acid polyesters based on terephthalic or isophthalic acid arecommercially available and convenient. Suitable hydroxy compounds forthese polymers typically includes ethylene glycol, propylene glycol,butylene glycol and 1,4-di-(hydroxy methyl)cyclohexane.

Suitable polyesters for use in the present invention typically have anintrinsic viscosity in the range of 0.6 to 1.2, and more particularly0.7 to 1.0 (for a 60/40 blend of phenol/tetrachloroethane solvent). ForPET an intrinsic viscosity value of 0.6 corresponds approximately to aviscosity average molecular weight of 36,000, and an intrinsic viscosityvalue of 1.2 to a viscosity average molecular weight of 103,000.

In general, suitable polyesters may include polymer linkages, sidechains, and end groups not related to the formal precursors of thesimple polyesters previously specified.

The blend also suitably comprises a polyamide material. Both aromaticand aliphatic polyamides can be used. Copolymers of polyamides and otherpolymers may also be used.

A preferred aromatic polyamide is a polymer formed by polymerizingmetaxylylenediamine (H₂NCH₂-m-C₆H₄—CH₂NH₂) with adipic acid(HO₂C(CH₂)₄CO₂H), for example a product manufactured and sold byMitsubishi Chemicals, Japan, under the designation MXD-6 (e.g., grades6001 and 6007).

Other suitable polyamides include, for example, nylon (e.g., nylon-6,6),GRIVORY (e.g., GRIVORY G16, G21, which are copolyamides having bothlinear aliphatic units and ring-like aromatic components, available fromEMS-Chemie Inc.) and VERSAMID (an aliphatic polyamide typically used asan ink resin and available from Cognis Corporation).

The proportion of polyamide in relation to polyester can be variedmainly in view of the intended use of the container.

In one embodiment of the present invention, the composition comprises ablend of a polyethylene terephthalate material and a polyamide material,wherein the blend preferably comprises less than 70% by weightpolyethylene terephthalate material. For this embodiment, the blend morepreferably comprises between 10 and 70% by weight polyethyleneterephthalate material, and most preferably between 20 and 60% by weightpolyethylene terephthalate material. Also for this embodiment, the blendpreferably comprises more than 20% by weight of the polyamide material,more preferably between 30 and 60% by weight polyamide material, andmost preferably between 40 and 55% by weight polyamide material.

In another embodiment of the present invention, the compositioncomprises a blend of a polyester and a polyamide, wherein the blendpreferably comprises more than 30% by weight polyamide material. Forthis embodiment, the blend preferably comprises more than 30% by weightpolyester, more preferably between 40 and 70% by weight polyester, andmost preferably between 45 and 70% by weight polyester. Also for thisembodiment, the blend more preferably comprises between 30 and 60% byweight polyamide material, and most preferably between 40 and 55% byweight polyamide material.

If desired, the blend may optionally also suitably comprise an oxygenscavenging material. While not intending to be bound by theory, it isbelieved that suitable oxygen scavenging materials form active metalcomplexes having capacity to bond with oxygen. In this manner, it isbelieved that the oxygen scavenging material can confer higher oxygenbarrier properties to the composition.

A broad variety of metallic and organic compounds are believed to beeffective in providing the oxygen scavenging effect, and an appropriatecompound may be selected based on cost and compatibility with thepolymers of the blend. A preferred embodiment is a transition metal or acomplex of metals selected from the first, second and third transitionseries of the periodic table, such as iron, cobalt, nickel, ruthenium,rhodium, palladium, osmium, iridium, and platinum. In another preferredembodiment, the metal compound comprises copper, manganese, or zinc.Suitable oxygen scavenging materials for use in this invention include:aluminum powder; aluminum carbide; aluminum chloride; cobalt powder;cobalt oxide; cobalt chloride; antimony powder; antimony oxide; antimonytri-acetate; antimony chloride III; antimony chloride V; iron;electrolytic iron; iron oxide; platinum; platinum on alumina; palladium;palladium on alumina; ruthenium; rhodium; copper; copper oxide; nickel,and mixed metal nanoparticles (e.g., cobalt iron oxide nanoparticles).Suitable nanoparticles have an average particle size of less than about200 nm, preferably less than about 100 nm, and more preferably between 5and 50 nm.

While not intending to be bound by theory, it is presently believed thatone possible advantage mixed metal nanoparticles might have is thatcobalt ferrite undergoes an internal charge transfer from cobalt to ironunder the illumination of a tungsten halogen lamp. As part of thecommercial bottle blowing process, preforms are sometimes heated underdirect irradiation of quartz halogen lamps. Although cobalt ferrite-typescavengers may absorb oxygen upon formation with the polyamide, it isanticipated that the scavenging activity would be substantiallyincreased as a result of the intense illumination during bottleformation. In addition, cobalt ferrite nanoparticles are prepared as ananocrystalline material. It is expected that the nanometer scale of theparticles may render them suitable for use in colorless, opticallytransparent containers, and that their crystalline structure would giverise to higher activity than solution salts of the same ions.

One skilled in the art can determine without much difficulty whichconcentration is appropriate in each blend, but in general it will be arange of 50-10,000 ppm by weight, and more preferably 50-1,000 ppm. Theupper limit is dictated by factors such as economy, toxicity, clarityand color.

There are numerous multilayer preform and container constructionspossible, each of which may be adapted for a particular product and/ormanufacturing process. A few representative examples will be given.

A suitable three-layer construction comprises a core barrier layerdisposed between inner and outer layers. For example, the three-layersidewall construction may comprise inner and outer layers of PET (e.g.,substantially virgin PET); and a core layer including a blend of (i) oneor more polyesters (e.g., PET, PC-PET, PETG, PEN, PBT), (ii) one or morepolyamides (e.g., MXD-6), and (iii) optionally one or more oxygenscavenging materials (e.g., cobalt).

A suitable five-layer structure may have relatively thin inner and outerintermediate layers to provide high oxygen barrier properties withoutloss of clarity. Relatively thicker inner and outer layers of PET wouldprovide the necessary strength and clarity. A thin core layer asdescribed above provides the necessary barrier effect at a competitiveprice and with accelerated activation. Suitable inner and outerintermediate layers for this embodiment may comprise oxygen barrierlayers such as EVOH, PEN, polyvinyldene chloride (PVDC), nylon 6, MXD-6,LCP (liquid crystal polymer), amorphous nylon, polyacrylonitrile (PAN),styrene acrylonitrile (SAN), and active scavengers such as AMOSORB fromBP/AMOCO.

An alternative five-layer structure may have inner and outer layers ofPET, inner and outer intermediate layers of PC-PET, and a thin corelayer as described above. The advantage of this embodiment is that thePC-PET may be effectively encapsulated in the bottle and not come indirect contact with the product or the user.

In preferred embodiments, the core layer has a thickness of betweenabout 1 and 10, more preferably between about 2 and 8, and mostpreferably between about 3 and 6 percent of the total wall thickness.

The container of the present invention may be used to provide good gas(e.g., oxygen and/or CO₂) barrier properties for products such ascarbonated soft drinks. It is particularly useful in packaging productssuch as beer, because beer rapidly loses its flavor due to oxygenmigration into the bottle. This is also true for products such as citrusproducts, tomato-based products, and aseptically packaged meat.

In preferred embodiments, the blends of the present invention, whenformed into three-layer (PET-Blend-PET), ten-ounce (295 ml) beveragebottles having a total wall thickness of 0.051 cm and a core layer of 5%of the total wall thickness, exhibit less than 15% loss of CO₂, whentested as described in Examples 1-3, over a 7.5 week period. Morepreferably the loss of CO₂ over that same period is less than 12% andmost preferably is less than 10%.

In preferred embodiments, the blends of the present invention, whenformed into three-layer (PET-Blend-PET), ten-ounce (295 ml) beveragebottles having a total wall thickness of 0.051 cm and a core layer of 5%of the total wall thickness, exhibit less than 0.02 cc/pkg/daytransmission of O₂, when tested as described in Examples 1-3. Morepreferably the transmission of O₂ over that same period is less than0.01 cc/pkg/day, and most preferably is less than 0.005 cc/pkg/day.

In preferred embodiments, the blends of the present invention, whenformed into multi-layer bottles, have superior layer-to-layer laminationstrength to formable polymers when compared to barrier materials used inconventional multi-layer bottles having reduced permeability. It is asurprising discovery that such superior layer-to-layer laminationstrengths have been achieved while not negatively impacting the bottle'sbarrier properties. As used herein, the term “superior layer-to-layerlamination strength” means that adjacent layers of a multi-layeredbottle have sufficient layer-to-layer lamination strength to withstandtypical stresses that such bottles experience in normal production,filling, storage and handling without appreciable amounts ofdelamination. While not intending to be bound by theory, it is presentlybelieved that the blends of the present invention achieve such superiorlayer-to-layer lamination strength as a result of the compatibility ofcertain components of the layers. For example, a presently preferredthree-layer bottle comprises inner and outer PET layers with anintermediate layer comprising a blend containing PET. It is believedthat having at least 10 weight percent (more preferably at least 20weight %, and most preferably at least 30 weight %) PET in theintermediate layer of such bottles contributes to the surprisingly goodlayer-to-layer lamination strength.

Preferred multi-layered constructions, when formed into 473 ml (16ounce) bottles, have sufficient layer-to-layer lamination strength toallow a full bottle to withstand (or substantially withstand) a drop of46 cm (18 inches) without appreciable delamination. More preferredbottles withstand a drop of over 1.2 m (4 feet), optimally over 1.8 m (6feet) without appreciable delamination. More preferred bottles are alsocapable of being stacked in a vending machine and dispensed withoutappreciable delamination. Notably, certain conventional multi-layeredbottles have exhibited significant amounts of delamination under thesestresses. Delaminated bottles are both esthetically unpleasing andstructurally flawed.

FIGS. 1-2 show two alternative multi-layer preform structures, and FIGS.3-6 show two alternative container structures, useful in the presentinvention.

FIG. 1 shows a substantially amorphous and transparent three-layerpreform 70 having an open upper end 71 with a neck finish includingouter threads 72 and a cylindrical flange 73. Below the neck flangethere is a substantially cylindrical body portion 74, terminating in aclosed hemispherical bottom end 75.

The three-layer sidewall construction includes outer layer 76, corelayer 77, and inner layer 78. By way of example, the inner and outer(exterior) layers (78 and 76) may be virgin bottle grade PET, while thecore layer 77 comprises the blend composition of this invention. In alower base-forming portion of the preform, a five-layer structure mayoptionally be formed by a last shot of virgin PET that clears theinjection nozzle of the blend composition (so it is filled with virginPET for preparation of the next preform). The last shot 79 of virgin PETforms a five-layer structure around the gate, and in this case thevirgin PET extends through to the exterior of the preform at the gateregion. The dimensions and wall thicknesses of the preform shown in FIG.1 are not to scale. Any number of different preform constructions may beused.

FIGS. 3-4 show a representative three-layer, container that may be blowmolded from a preform similar to that shown in FIG. 1. The container 110includes an open top end 111, substantially cylindrical sidewall 112,and closed bottom end 113. The container includes the same neck finish114 and flange 115 of the preform, which are not expanded during blowmolding. The sidewall includes an expanded shoulder portion 116increasing in diameter to a cylindrical panel portion 117, whichincludes a plurality of vertically-elongated, symmetrically-disposedvacuum panels 118. The vacuum panels are designed to move inwardly toalleviate the vacuum formed during product cooling in the sealedcontainer. Again, this container construction is by way of example onlyand the invention is not limited to any particular package structure.FIG. 4 shows the three-layer sidewall construction including inner layer120, core layer 121, and outer layer 122. By way of example, the innerand outer layers (120 and 122) may be virgin bottle grade PET, while thecore layer 121 is made of the blend composition of this invention.

FIG. 2 shows an alternative five-layer preform 90. Again, the preformincludes an open upper end 91, neck finish with threads 92 and flange93, and body-forming portion 94 with a closed bottom end 95. Thefive-layer sidewall construction includes outer layer 96, firstintermediate layer 97, core layer 98, second intermediate layer 99, andinner layer 100, disposed in serial order. By way of example, the innerand outer layers 96 and 100 may be virgin bottle grade PET, while theintermediate layers 97 and 99 are a PC-PET material or a high oxygenbarrier material such as EVOH, and the core layer 98 is made of theblend composition of this invention. Again in the base, there optionallymay be a last shot of virgin PET 101 to clear the nozzle.

FIGS. 5-6 show a representative ketchup container that may be blowmolded from a five-layer preform similar to that of FIG. 2. Again, thedetails of the preform and container construction are not critical, andvariations may be required to the preform construction in order to blowmold the container of FIG. 5. The ketchup container 130 includes an opentop end 131, neck finish 132 with neck flange 133, a shoulder portion134 increasing in diameter, and a panel portion 135 connecting to a base136. The five-layer sidewall construction, as shown in FIG. 6, includesan inner layer 137, first intermediate layer 138, core layer 139, secondintermediate layer 140, and outer layer 141. By way of example, theinner and outer layers 137 and 141 may be virgin bottle grade PET, thecore layer may be the blend composition of the present invention, andthe intermediate layers 138 and 140 may be a PC-PET material or a highoxygen barrier material such as EVOH.

Several different methods are practiced to make the containers of thepresent invention.

In one method, a multilayered container is prepared by: (i) providing acore layer blend material of the present invention; (ii) providing aninner and outer layer material of a suitable formable polymer; (iii)co-injecting the core layer blend material and the inner and outer layermaterials to form a multilayered preform; and (iv) heating and expandingthe preform to form a container.

In an alternative method, a multilayered container is prepared by: (i)providing a core layer blend material of the present invention; (ii)providing an inner and outer layer material of a suitable formablepolymer; (iii) extruding a multilayer parison tube having inner andouter layers of a suitable formable polymer and a core layer blendmaterial of the present invention; (iv) clamping the parison tube into ahollow cavity mold; (v) blowing the parison against the cavity; and (vi)trimming the molded container.

In yet an alternative method (the “over-injected parison” method), amultilayered container is prepared by: (i) providing a core layer blendmaterial of the present invention; (ii) providing an inner and outerlayer material of a suitable formable polymer; (iii) extruding amultilayer parison tube having inner and outer layers of a suitableformable polymer and a core layer blend material of the presentinvention; (iv) injecting one or more additional layers of polymer overthe parison; (v) clamping the over-injected parison tube into a hollowcavity mold; (vi) blowing the over-injected parison against the cavity;and (vii) optionally trimming the molded container.

In yet another method (called “IOI”), a multilayered container isprepared by: (i) providing a blend material of the present invention;(ii) providing a material of a suitable formable polymer; (iii)injecting the blend material to form a preform; (iv) injecting a layerof formable polymer against the preform (e.g., on the outside surface);and (v) heating and expanding the preform to form a container.

The following examples are offered to aid in understanding of thepresent invention and are not to be construed as limiting the scopethereof. Unless otherwise indicated, all parts and percentages are byweight.

EXAMPLES Examples 1-3

Examples 1-3 illustrate the barrier properties of various multilayercontainers. Ten-ounce (295 ml) carbonated soft drink (CSD) preforms werecoinjected in an Arburg press fitted with a Kortec coinjection unit andstretch blowmolded in a Sidel blowmolding unit.

For the core layer of the preforms, the materials listed in Table 1 wereblended at 275-280° C. at 100 rpm in a twin screw extruder model ZSK-25manufactured by the Werner and Pfleiderer Corporation and pelletizedunder air cooling. For each formula, approximately 4.5 to 6.8 kg ofresin was blended. The PET, PEN, and MXD6 materials used were driedprior to use in a Conair drier at 121° C.

Twenty to fifty preforms were injected and stretch blowmolded. Eachpreform had a core layer of the composition described in Table 1 and aninner and an outer layer of PET. The thickness of the core layer wasabout 5% of the total container wall thickness of 0.051 cm.

Examples C1 and C2 were included for comparison purposes.

TABLE 1 Composition of Materials PET¹ MXD6² PEN³ Cobalt⁴ Example wt % wt% wt % wt % 1 46.00 53.95 0.05 2 46.00 54.00 3 50.00 25.00 25.00 C1100.00  C2 100.00  ¹Eastapak 9663 PET was used as supplied by EastmanChemical ²MXD6 Grade 6007 was used as supplied by the Mitsubishi GasCorporation ³Hypertuf 92004 PEN was used as supplied by Shell Chemical⁴Cobalt Neodecanoate was used as supplied by OMG Americas

CO₂ transmission measurements were performed on a computer controlledpressure measurement system. The bottles were threaded into a gasmanifold and charged with 4 atmospheres of CO₂ gas and maintained atambient temperature and humidity for the 7½ week period. Each bottleunder test is monitored with an independent pressure transducer, and thepressure is periodically measured and recorded by an automated dataacquisition program.

O₂ transmission measurements were performed on a Mocon Oxtran 2/20 ModelML and SM that was adapted for use with 10 oz (295 ml) bottles, and werecarried out at ambient temperature and humidity. Bottles wereconditioned for 24 to 48 hours prior to each measurement.

TABLE 2 Permeability—10 oz containers O₂ Transmission Example % CO₂ Loss(cc/pkg/day) 1 Not tested 0.0021 2  7.7 0.0096 3 11.1 0.0168 C1 24.70.0296 C2  7.0 0.0085

The O₂ transmission rate determined for Examples 1 and 2 were identicalimmediately after the bottles were produced. After approximately 30 daysat ambient temperature and humidity, the scavenging effect of Example 1reduced the O₂ transmission rate to the minimum sensitivity level forthe Mocon ML system.

As is evident from the data in Table 2, the blends exhibited both O₂ andCO₂ barrier performance that was significantly higher than would havebeen expected based upon the proportion of MXD6 alone. In the case ofExample 1, the O₂ permeability differed from the neat barrier materialby 13 percent, whereas the proportion of MXD6 differed by a factor ofabout 2. The 295 ml bottles of Examples 1-3 also exhibited acceptablelamination strength for their intended use.

It has been discovered that bottle design and moisture and/or humidityconditioning can influence the onset of O₂ scavenging effect.Sixteen-ounce (473 ml) heat set bottles (weighing 38 g) having thegeneral construction indicated above were tested for O₂ transmission asoutlined above except the bottles were conditioned prior to testing asdescribed below.

TABLE 2b Permeability—473 ml (16 oz) containers O₂ Transmission ExampleStorage Condition Prior to Testing (cc/pkg/day) 1 24 hours at ambienttemperature and humidity 0.012 1 Filled with coldwater for 5 minutes,drained  0.00036 and then tested 1 5 weeks at ambient temperature andhumidity 0.025 1 5 weeks at ambient temperature and humidity 0.002 thenpasteurized at 82° C. for 5 minutes C1 24 hours at ambient temperatureand humidity 0.04 

As can be seen moisture is a factor that strongly influences how quicklythe oxygen scavenging effect is observed.

A BRUCETON Staircase drop test was conducted on filled sixteen-ounce(473 ml) heat set bottles (weighing 38 g). These bottles weremanufactured using the “over-injected parison” method and hot filled at183° F. (84° C.). When blown the bottles had 4 layers of material (i.e.,the inner three layers were initially formed with the parison and theouter layer was over-injected). From inside to outside a cross-sectionof the bottles had the following layers (parts by weight): PET (4parts)//Ex. 1 blend (4 parts)//PET (4 parts)// PET (88 parts).

The BRUCETON staircase method involves dropping filled bottles apredetermined distance and observing whether the bottle exhibited anydelamination. 20 bottles were used in this test. All 20 bottles weretested from a height of 45.7 cm (18 inches) and passed the test (i.e.,no visible delamination). The bottles were then tested from higherheights (1.2 m, 1.5 m, 1.8 m, 2.1 m). Each bottle was tested once. Ifthe bottle passed the next bottle was tested from the next higherheight. If that bottle passed the next bottle was tested at the nexthigher height, etc. If a bottle failed the height was reduced for thenext bottle, etc.

Table 2C illustrates the results for this test

TABLE 2C BRUCETON STAIRCASE DROP TEST Drop Height Bottle # 1.2 m (4 ft.)1.5 m (5 ft.) 1.8 m (6 ft.) 2.1 m (7 ft.) A 1 B 1 C 1 D 0 E 1 F 0 G 1 H0 I 1 J 1 K 1 L 0 M 1 N 0 O 0 P 1 Q 1 R 0 S 1 T 0 1 = pass; 0 = fail

As can be seen from the above data the bottles of the present inventionexhibited excellent lamination strength. A control bottle having a pureMXD6 barrier layer would typically exhibit failure at about 25 to 30 cm(10 to 12 inches) drop. All the above bottles passed at 1.2 m (4 ft.)and an average failure height of greater than 1.8 m (6 ft.) wasobserved.

Examples 4-6

Examples 4-6 illustrate other blends that are believed to be suitablefor use in the preforms and containers of the present invention.

TABLE 3 Composition of Materials 6001- 6007- PET¹ MXD6² MXD6³ HDPE⁴Sample wt % wt % wt % wt % 4 65 15 20 5 60 30 10 6 60 30 10 ¹Eastapak9663 PET was used as supplied by Eastman Chemical ²MXD6 Grade 6001 wasused as supplied by the Mitsubishi Gas Corporation ³MXD6 Grade 6001 wasused as supplied by the Mitsubishi Gas Corporation ⁴Exxon Escorene HDPEwas used as supplied by Exxon.

Example 7 Preparation of Cobalt Ferrite Nanoparticles

A solution of 5.40 g FeCl₃.6H₂O and 2.38 g CoCl₂.6H₂O in 200 ml HPLCgrade H₂O was prepared and added dropwise over a period of 5 minutes toa stirred solution of 8.0 g NaOH in HPLC grade H₂O at ambienttemperature. The resulting brown precipitate and solution were coveredwith a watch glass and heated to boiling for one hour. The solution wascooled to ambient temperature, the supernatant solution was poured fromthe black precipitate, and the precipitate was washed once with water.The cobalt ferrite was annealed for 24 hours at 250° C. in an oven, andthe resulting black solid was crushed to a fine powder in a mortar andpestle.

Example 8

3.78 g of Cobalt Ferrite was mixed vigorously with 5.4 kg EastmanEastapak 9663 PET which had been previously dried in a Conair Dryer. Tothis mixture was added 2.72 kg Mitsubishi MXD6 6001 and 0.9 kg ExxonEscorene 6704 HDPE. The mixture was melt blended and pelletized in aWerner and Pfleiderer twin screw extruder at 275° C. at a rate ofapproximately 13.6 kg/hour. The resulting material was stored undernitrogen.

Having thus described the preferred embodiments of the presentinvention, those of skill in the art will readily appreciate that theteachings found herein may be applied to yet other embodiments withinthe scope of the claims hereto attached. The complete disclosure of allpatents, patent documents, and publications are incorporated herein byreference as if individually incorporated.

1. A multi-layered container, comprising: a layer of a formable polymer;and a blend layer comprising a blend of: (i) between 10 and 60% byweight of a polyethylene terephthalate material, (ii) between 45 and 60%by weight of a polyamide material, (iii) 50 to 10,000 ppm of an oxygenscavenging material, and wherein said blend layer comprises betweenabout 3 and 6 percent of the total wall thickness of the container andwherein the percent polyamide material in the entire container isbetween 1.35 and 3.6% by weight.
 2. The container of claim 1, whereinthe layer-to-layer lamination strength is sufficient such that a filled473 ml bottle can withstand a drop of 46 cm without appreciabledelamination.
 3. The container of claim 1, wherein the layer-to-layerlamination strength is sufficient such that a filled 473 ml bottle canwithstand a drop of 1.2 m without appreciable delamination.
 4. Thecontainer of claim 1, wherein the blend comprises between 45 and 60% byweight PET.
 5. The container of claim 1, wherein the blend comprisesbetween 30 and 60% by weight MXD6.
 6. The container of claim 1, whereinthe blend comprises between 40 and 55% by weight of the polyamidematerial.
 7. The container of claim 1, wherein the container, is athree-layer (PET-Blend-PET), 295 ml beverage bottle haying a total wallthickness of 0.051 cm and a core layer of 5% of the total wallthickness, said container exhibits less than 15% loss of CO₂ over a 7.5week period.
 8. The container of claim 1, wherein the container, is athree-layer (PET-Blend-PET), 295 ml beverage bottle having a total wallthickness of 0.051 cm and a core layer of 5% of the total wallthickness, said container exhibits less than 0.02 cc/pkg/daytransmission of O₂.
 9. A preform for expansion into the container ofclaim
 1. 10. The container of claim 1, wherein said blend layercomprises 50-1,000 ppm of an oxygen scavenging material.
 11. Thecontainer of claim 1, wherein the formable polymer comprises a formablepolyester which is selected from the group consisting of PET, PC-PET,PETG, PEN and PBT.
 12. The container of claim 11, wherein the blendcomprises between 20 and 60% by weight PET and wherein the polyamidecomprises MXD6.
 13. The container of claim 1, wherein the oxygenscavenging material forms active metal complexes having capacity to bondwith oxygen for conferring high oxygen barrier properties to thecomposition.
 14. The container of claim 13, wherein the oxygenscavenging material comprises cobalt.
 15. The container of claim 13,wherein the oxygen scavenging material comprises mixed metalnanoparticles.